In which of the following will a piece of iron weigh most?
in air
in an atmosphere of oxygen
in an atmosphere of CO2
in vacuum
Correct Answer :
D. in vacuum
Related Questions
Water has maximum density at
0° C
-15° C
4° C
15° C
The speed at which light travels in vacuum is
3 x 107 ms-1
5 x 108 ms-1
3 x 104 kms-1
3 x 108 ms-1
The distance between two bodies is halved. Now the force of attraction between them will be
half
one fourth
four times
two times
The device that is used to measure the electromotive force of a cell is
an ammeter
a rheostat
a voltmeter
a voltameter
When sound waves travel from one medium to another, the quantity which remains unchanged is its
speed
frequency
wavelength
All the above
Meteors
look like falling stars
are really pieces of rock or metal
burn up as they shoot through the air
All the above
The largest planet in the solar system is
Neptune
Uranus
Jupiter
Saturn
The filament used in the electric lamp is made of
nichrome
tungsten
copper
aluminium
When a bullet is fired from a gun
the gun moves forward
the gun jumps up
the gun does not move
the gun recoils with the same momentum as the bullet
Chronometer is an instrument to measure
heat
electric potential
time
distance between two points
The extremely luminous objects located at the centre of some distant galaxies and which are sources of high energy electromagnetic radiation are known as
Nebulae
Quasars
Meteors
Comets
A boat loaded with rocks floats in the middle of a swimming pool. A man in the boat throws the rocks overboard. The level of water in the pool will
increase
decrease
remain the same
first decrease and then increase
A piece of cork is embedded inside an ice block which floats in water. What will happen to the level of water when all ice melts?
It will go down
It will come up
It will remain at the same level
First it will go down and it will come up
An ammeter has
a high resistance
a very low resistance
no resistance at all
resistance of 400 ? w
Which physical quantity is measured in watts
power
kinetic energy
momentum
impulse
If an empty cylinder Is half ruled with a liquid, Its centre of gravity is
shifted upwards
shifted downwards
shifted neither upward nor downward
shifted upward or downward depending on the density of the liquid
The unit of power in SI is
Joule
Newton
Joule/Sec
Erg/Sec
The spectrum of white light can be studied by
a microscope
a telescope
a stereoscope
a spectroscope
When a body is projected upwards
the time for the upward journey and downward journey are the same
the upward journey takes more time
the downward journey takes more time
Cant be said
The completely dark portion of a shadow of an object is known as
umbra
penumbra
image
black portion of light
The atmosphere gets heated up mainly by
direct sun's rays
radiation from earth's surface
radiogenic heat (resulting from radioactive decay)
cosmic rays coming from space
An electric charge is measured in
coulomb
ampere
volt
watt
Choose the correct answer
Microphone converts sound energy into electrical energy.
Electric fan converts electrical energy into mechanical energy.
Battery converts chemical energy into electrical energy.
All the above
Velocity of sound in high altitudes is low because at such a height
the temperature is low
there is no air
the pressure is low
All the above
X-rays are used
in hospital in the treatment of malignant growth
to reveal hidden flaws in metal castings and welded joints
to detect alterations made in works of art
All the above
When a body is partly or wholly immersed in a liquid the apparent loss of weight is equal to the weight of the liquid displaced by the submerged portion. This is known as
Pascal's law
Bernoulli's law
Archimedes' law
Boyle's law
The planet that has got a well-developed set of rings is
Venus
Saturn
Mercury
Earth
The temperature of a large bucket-full of hot water (a few degrees below boiling point) is lower than a beaker full of boiling water. But
the hot water contains a much larger quantity of internal energy than the boiling water
the boiling water contains more quantity of internal energy than the warm water
both of them have got the same amount of internal energy.
nothing can be said definitely with the data given
A lightning conductor installed in a building
does not allow the lightning to fall on the building at all
drives away the charged clouds
forces the lightning to fall on other buildings near that building
conducts the electric charges to the ground when lightning strikes the building
When light travels from one medium to another there is a change in its
velocity
wavelength
frequency
Both (a) and (b) above